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Herbal Medicines and Heavy Metals

Herbal Medicines and Heavy Metals

Heavy metals are naturally occurring elements widely distributed in the environment. They can be absorbed into the human body through sources such as water, food or air, and may cause harmful health effects when exceeded certain levels. The heavy metals of major concern to the human health include arsenic, cadmium, lead and mercury.

Why some herbal medicines contain higher level of heavy metals?

Contamination during processing of herbal medicinesUse of containers that release heavy metals, or use of additives containing heavy metals during processing.

Maintain a proper transaction recordLicensed retailers and wholesalers of Chm should maintain all transaction records in accordance with the Chinese Medicines Regulation (Cap.549F of the Laws of Hong Kong) and practising guidelines prepared by the Chinese Medicine Council of Hong Kong. This facilitates timely tracing of the concerned herbal medicines and their corresponding distribution channels when necessary.

Advice to the public

Rinse the herbal medicines before decoctingHerbal medicines should be rinsed under running water before decocting in order to remove heavy metal contaminants in the mud and sand attached on the surface of the herbal medicines.

Use ceramic containers for decoctingMetal containers may easily react with ingredients of the herbal medicines and then release metal ions, hence, chemically-stable containers such as ceramic containers should be used.

Consume the decoction onlyAfter decocting, the active ingredients of the herbal medicines have already dissolved into the decoction. Studies have shown that even if the herbal medicines are contaminated by heavy metals, most of the heavy metals retain in the herbal medicine residues after decocting. It is therefore advised to consume the decoction only but not the herbal medicine residues.

Use herbal medicines as instructed by Chinese medicine practitionersChinese medicine practitioners should be consulted prior to the use of herbal medicines. It is advised to adhere to the decocting method, consumption time and dosage as prescribed. Once recovered, one should stop consuming the herbal medicines and avoid unnecessary prolonged consumption.

Purchase herbal medicines from licensed retailersPurchasing herbal medicines from licensed retailers ensures that the herbal medicines come from reputable suppliers and therefore, reducing the risk of buying herbal medicines which may contain high levels of heavy metals as a result of adulteration or improper processing.

The information in this pamphlet may be re-disseminated or reproduced, provided that the Chinese Medicine Division (CMD), as the source of information, is acknowledged and that the re-dissemination or reproduction is for non-commercial use. Any other reproduction, adaptation, distribution, dissemination or making available of the information in this pamphlet for commercial use is strictly prohibited unless prior written authorization is obtained from the CMD.